How to Open the Back of Xiaomi Mi 8: A Complete Disassembly Guide

Xiaomi Mi 8 smartphone, released in 2018, became a landmark device thanks to the introduction of the new model AMOLED-screen, face recognition system Face ID and two-frequency navigation GPS. But time is relentless: even the most reliable batteries are degraded, and the glass elements of the case are not immune to accidental falls, and it is at this point that the owner is faced with the question of how to carefully open the device to replace damaged parts without contacting the service center.

The process of disassembling this device requires not only technical skills, but also an understanding of the specifics of the design, where the rear panel is glued around the perimeter. Incorrect opening can damage the plumes of the fingerprint scanner or cracks on the lid itself, so it is important to prepare the workplace and a specialized tool in advance. In this article, we will look at each step, from heating the glue to turning off the plumes, to minimize the risks.

Before you start to physically affect the body, you need to make sure that all the necessary components for repairs. Often enthusiasts forget that reassembling will require a new adhesive composition, as the old loses its adhesive properties after heating and mechanical separation. The factory adhesive Xiaomi Mi 8 is an elastic polymer tape that softens at 80-90 degrees Celsius, but does not melt completely.

Tools and workplace preparation required

The use of improvised tools such as kitchen knives or needles is strongly discouraged, as they can damage internal components or leave deep scratches on the frame. You will need a professional kit that will ensure process control and device safety.

The main tool will be the heating element, which can be a special heater for phones, a temperature-adjusted thermophen or, in extreme cases, a sealed heating pad. Temperature is critical: overheating can spoil the heat. OLED-display, which is immediately under the back cover, and underheating will lead to breakage of the glass when trying to detach.

• 🔧 A set of precision screwdrivers (Pentalobe and Phillips) for frame screws.
• 🔥 Thermophen or heating pad for uniform heating of the glue layer.
• 🎴 Plastic cards, mediators or thin metal blades for opening.
• 🧲 Magnetic mat for sorting screws of different sizes.
• 🧪 Isopropyl alcohol or special solvent of glue (B-7000).

The organization of the workspace is half of the success. The light should fall evenly, without glare, so that you can see the small parts and fasteners, and it is also worth taking care that there are no metal objects at hand that could accidentally fall on an open motherboard and cause a short circuit.

Safety Techniques and Precautions

There are risks to working with lithium polymer batteries and fragile glass panels. Even a phone that is turned off stores a residual charge that, if handled carelessly, can disable the power controller. Electrical safety is a must when dealing with mobile electronics.

⚠️ Warning: Before starting any work, be sure to completely turn off the smartphone. Do not try to disassemble the device if the battery is swollen - this can lead to its fire when punctured.

Special attention should be paid to eye protection. If you carelessly handle the glass back cover can burst, flying into small fragments, work better with safety glasses or at least keep your face at a safe distance from the opening area. In addition, static electricity can damage the chips, so it is advisable to use an antistatic bracelet or periodically touch a ground metal object.

It is important to understand that the moisture protection of the device after opening will be broken. Factory sealing Xiaomi Mi 8 is quite high quality, but after repairs, you should not count on it. If you plan to use the phone in high humidity conditions, you will need additional treatment of the perimeter of the body with a high-quality sealant.

Another safety aspect is the glue itself: some solvents can emit caustic fumes, so the room should be well ventilated. Use only proven chemical compounds designed to repair electronics so as not to damage plastic frame elements or chamber coatings.

The process of heating and separation of the back cover

The most important step is to soften the adhesive layer. The rear panel of the Xiaomi Mi 8 is glued around the perimeter, and the adhesive is distributed unevenly: in some places, its layer is thicker, especially in areas around the camera modules.

Once the body has been heated to a comfortable temperature (about 40-50 degrees to the touch outside), you can start creating a gap. Use a suction cup to slightly raise the edge of the glass, and in the resulting gap carefully insert a plastic map or a thin blade. The movements should be sliding, parallel to the plane of the screen, so as not to damage the glass.

Move the tool around the perimeter of the device, methodically cutting the adhesive layer. Be especially careful at the bottom of the smartphone, where the fingerprint scanner plume is located, it is glued to the inside of the lid and connects to the motherboard. Excessive force or a sharp jerk can break this thin conductor, which will make the scanner inoperable.

• 🔥 Heat the body evenly, moving the heat source around the perimeter.
• ✋ Do not try to remove the cover completely until you have passed the entire circuit with the tool.
• 🔌 Be very careful in the lower part where the plume passes.
• 🧩 Use a suction cup to create an initial gap without damaging the glass.

When you pass the tool around the perimeter, the back cover should be easy to separate, but don't be too quick to put it down: it's still connected by a plume. Carefully bend the lid, like a page of a book, to access the internal components and disable the connector.

Dismantling internal components and protection of boards

When you take the back off, you see the inside of the smartphone, and you have a battery in most of the space, and you have a motherboard in the top, and it's covered with a black plastic cover, and it's not only decorative, it's also protective of the board from dust and mechanical damage, and it's shielding the radio.

To access the main nodes, you need to twist the screws that fix the protective plate. The Xiaomi Mi 8 uses many screws of different lengths, and it is crucial not to confuse them when assembled. A long screw screw screw screw screwed into the hole for a short one can penetrate the motherboard through, causing irreversible damage.

When the safety plate is removed, the connectors are accessed. The first thing you do is turn off the battery. It's the golden rule of electronics repair: shutting down the device before disconnecting the other plumes prevents short circuits and power surges. Use a plastic blade to gently snap the connector.

And then you can disconnect the fingerprint scanner plume, which runs from the bottom of the case to the board, and it can be attached with extra glue or a pinch, and you can be gentle, because it's a difficult and often not cost-effective task to restore that plume.

💡

Before turning off any plume, take a picture of its position, which will help to properly stow it back when assembled, avoiding clamps and tension.

Battery replacement and device assembly

If the purpose of disassembly was to replace the battery, after turning off the plumes, you need to remove the old element. The battery in Xiaomi Mi 8 is also planted on glue, so to extract it will require reheating the back of the device (if you shoot through the back cover) or using special hoods. Do not use metal objects to tweak the battery - a puncture can cause a fire.

Once you have a new battery installed, make sure it sits tightly in its bed and the connector is securely snapped. Before final assembly, it makes sense to test the battery, press the power button and check if the display is responding and charging, which will avoid re-disassembly in the event of a new part failing.

The final step is assembly. Apply the new adhesive compound around the perimeter of the body. You can use a pre-made adhesive tape cut out in shape or a liquid adhesive B-7000. In the second case, apply a thin strip and let it dry for 1-2 minutes to the state of Velcro. Press the back cover tightly and lock the device with rubber rings or a load for 15-20 minutes.

It is important not to overdo it with glue: its excess can be squeezed into the case and get into the cameras or the charging connector. Equal distribution and moderate amount - the key to accurate results and maintaining moisture-protective properties (as much as possible after repair).

⚠️ Warning: Do not turn on the phone immediately after the lid is glued if you have used liquid glue. 2-3 hours to achieve maximum strength.

Frequent errors and expert recommendations

Disassembling modern smartphones is always a balance between effort and accuracy. Beginners often make the mistake of trying to open the phone immediately after a short heating. The glue inside the layers cools quickly, and if you don't have time to do the tool, the heating procedure will have to be repeated. Patience is more important than strength.

Another common problem is the loss of screws or their entanglement. the Xiaomi Mi 8 motherboard has a complex geometry of holes. Using a magnetic mat with markup or a regular paper circuit where you will lay the screws in the order in which you twisted, will save you from unnecessary problems when you build.

Do not ignore the condition of the plumes. When installing the back cover, make sure that no wires fall under the edge of the glass or screws. The pinched plume will eventually be rubbed or transmitted, which will cause the corresponding module (camera, antenna, scanner) to break.

If the back cover is cracked during the dismantling process, don't despair. The market offers many copies and original parts. The main thing is to carefully remove the shards of old glass from the frame so that the new cover will fall flat and without gaps. The remnants of old glue must be carefully cleaned with alcohol.

💡

The main secret of successful disassembly is not to rush to break off the lid and always turn off the battery before working with other components.